The GUARDIAN Trial is a double-blind, placebo controlled multinational trial to investigate the effects of a NA+/H+ exchange inhibitor (cariporide), (HOE 642) on patient mortality and myocardial infarction in patients who are at risk of myocardial damage due to coronary artery disease. The primary purpose of the study is to investigate whether cariporide can reduce the incidence of death and myocardial infarction in patients who are at risk of myocardial damage during a coronary interventional procedure or coronary artery bypass graft surgery. Additionally, the safety and tolerability of this new drug will be evaluated.